Until recently, Kevin Satizabal, a 25-year-old musician and online communities assistant for a nonprofit in London, could never visit a subway station without help. And he'd probably never do so at night, when finding assistance is more difficult.

That's because for a vision-impaired commuter, moving through an unfamiliar tube stop, with its many twists and turns, stairs and platforms, can be terrifying.

But last year, Satizabal entered the subway at London's bustling Pimlico station without the help of a companion—or, at least, not a human one. Wearing a pair of bone-conduction headphones, which enable a wearer to listen to electronic devices without blocking out ambient sounds or conversations, Satizabal was guided through the station by a navigation app on his smartphone, and by a network of Bluetooth beacons deployed throughout the station.

That app was designed by digital product studio ustwo. It was dubbed Wayfindr, which also came to be the name of a nonprofit that ustwo launched following a 2014 collaboration with the Royal London Society for Blind People (RLSB). Wayfindr, the nonprofit, is supported by a $1 million grant from Google's philanthropic arm, Google.org. Earlier this month, the group announced that it is offering app developers a kit that includes a demo app and guidelines, and is designed to encourage transit agencies to launch beacon-based audio navigation systems using the standard. Wayfindr hopes that its deployment guidelines will become an open standard for beacon-based public-transit navigation apps.

Wayfindr and its technology partners have also been testing apps based on the open standard, in partnership with public-transport agencies in London and Sydney.

Wayfindr trial in 2015 (Photo: Sophie Mutevelian)

Satizabal, whose employer is the RLSB, told me that he's not had great luck with other navigation systems he has tried because the verbal instructions tended to come slowly, leaving him waiting for the next step and unsure of where he is at any given moment. He and other vision-impaired individuals tested and evaluated iterations of the app at Pimlico and other London subway stations, providing feedback to the app developers. That feedback was incorporated into the app design and the Wayfindr standard. When Satizabal tested the Wayfindr-based app in the subway, he says, the navigation instructions were transmitted at exactly the right times. The accuracy—enabled by a dense network of Bluetooth beacons installed throughout the Pimlico station—was precise enough to tell him when the escalator he was on was halfway to its destination, or how many steps remained before he reached the top of the staircase.